Technetium-99m is the most widely used radiotracer in nuclear medicine. A rare combination of nuclear properties gives this radionuclide considerable advantages over other agents in diagnostic applications such as organ visualization and tumor localization. The development of a simple generator, over a decade ago, to elute Tc-99m from its parent makes it possible to use the isotope at great distances from the production site.
Technetium-99m is a useful tracer in nuclear medicine because of its short half-life (6 hours) and its gamma radiation energy (140 KeV) which has satisfactory tissue penetration and is easily collimated. The absence of beta radiation makes feasible the administration of millicurie amounts of Tc-99m with tolerable radiation dose to the patient.
However, the six hour half-life of Tc-99m makes it impossible to conduct chemical, in-vitro, and animal studies with Tc-99m labeled diagnostic agents that require a longer study period. Because Tc-99m is the most important isotope in nuclear medicine, it is often advantageous to be able to conduct such long term studies and thus it would be advantageous to have a stand-in for Tc-99m that possessed a much longer half-life. It is known that Tc-96 has the desired longer half-life (4.35 days) while retaining the useful nuclear properties of Tc-99m. However, the previous methods of preparing Tc-96, the Nb(.sup..alpha.,n) reaction [Edwards, et al., Phys. Rev., 72, 384 (1947)], the .sup.96 Mo(p,n) reaction [Monaro, et al., Can. J. Phys., 46, 2375 (1968)], and the .sup.96 Mo(d,2n) reaction [Cesareo, et al., Zeit. Phys., 205, 174 (1967)] fail to produce the isotope in usable quantity and failed to produce material of the high specific activity needed for biomedical applications.
It is thus an object of the present invention to provide a process for preparing high specific activity Tc-96 useful in biomedical applications.
It is a further object of the present invention to provide a technique for preparing and purifying Tc-96 in quantities useful for nuclear medicine.